Quantification of platelet-associated IgG with competitive solid-phase enzyme immunoassay.
In order to measure platelet-associated IgG (PAIgG), we devised a solid-phase enzyme immunoassay employing a competitive binding of peroxidase-conjugated anti-IgG antiserum between platelets and polystyrene tubes coated with IgG. The amounts of peroxidase bound to the tubes were measured in a spectrophotometer by an enzymatic reaction. This method is highly sensitive, reproducible and can be carried out more simply. the PAIgG values of normal controls averaged 21.6 +/- 6.6 (SD) ng/10(7) platelets. 27 (93%) of 29 patients with idiopathic thrombocytopenic purpura (ITP), who had a platelet count of less than 15 X 10(4)/microliter, had PAIgG values greater than those of controls by 2 SD and averaged 205.5 +/- 323 ng. There was a significant inverse correlation between platelet count and PAIgG value of ITP patients. the PAIgG values of patients with aplastic anemia were within normal range.
D000293:Adolescent; D000328:Adult; D001792:Blood Platelets / Q000276:immunology*; D005260:Female; D006735:Horseradish Peroxidase; D006801:Humans; D007124:Immunoenzyme Techniques; D007074:Immunoglobulin G / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D010976:Platelet Count; D011696:Purpura, Thrombocytopenic / Q000276:immunology*
D007074:Immunoglobulin G; D006735:Horseradish Peroxidase